Process for the preparation and processing of a hydroxylammonium salt solution

Abstract

A process for the preparation and processing of a hydroxylammonium salt solution involves maintaining an aqueous acid reaction medium circulation between a hydroxylammonium salt synthesis zone and an oxime synthesis zone; continuously supplying nitrate ions or nitrogen oxides to be converted into nitrate, by way of nitrogen source for the formation of the hydroxylammonium salt, to the liquid being maintained in circulation; catalytically reducing the nitrate ions with hydrogen to obtain hydroxylamine; removing the ammonium ions, formed as a by-product in the reduction of the nitrate ions, by contacting the circulating liquid with a gas flow consisting of nitrogen oxides generated in catalytic combustion of ammonia. Advantageously, 0.01 to 5 wt. % of the nitrogen oxides formed in the combustion effect reduction of the ammonium ions to nitrogen, and the remainder of the nitrogen oxides are used for the preparation of nitric acid.

What is claimed is: 
     
       1. A process for producing hydroxylammonium salt solution, wherein an aqueous acid reaction medium which contains ammonia ions is continuously circulated between an hydroxylammonium salt synthesis zone and an oxime synthesis zone comprising the steps of: (i) continuously supplying nitrate ions or nitrogen oxides to be converted into nitrate by a nitrogen source to said aqueous acid reaction medium for formation of hydroxylammonium salt;   (ii) catalytically reducing said nitrate ions with molecular hydrogen to hydroxylamine, wherein ammonium ions are formed as a by-product in reduction of said nitrate ions;   (iii) removing said ammonium ions by conversion with nitrogen oxides by contacting said aqueous acid reaction medium with a gas flow containing 0.01 to 5 wt. % of the nitrogen oxides formed in catalytic combustion of ammonia;   (iv) utilizing remaining nitrogen oxide containing gas flow formed in said catalytic combustion of ammonia for preparation of nitric acid.   
     
     
       2. The process according to claim 1, wherein non-converted nitrogen oxides of the nitrogen oxide containing gas flow in step (iv) are recycled into a process for nitric acid production, said process for nitric acid production being the source for said nitrate ions used for formation of hydroxylammonium salt. 
     
     
       3. The process according to claim 1, wherein preparation of nitric acid is achieved by a commercial nitric acid production process having a capacity of 200 to 750 kt HNO 3  /year (dry). 
     
     
       4. The process according to claim 1, wherein 0.5-3 wt. % of said nitrogen oxides formed in the combustion effects conversion of ammonium ions into nitrogen. 
     
     
       5. The process according to claim 1, wherein in step (i) nitrate ions in the form of nitric acid are continuously supplied.